. Optimization of total lipid extraction from biomass by pretreatment
methods
The algal cells were destructed with four different methods
such as ultrasonication, autoclave, deep-freezing and microwave,
respectively. Among them, the maximum lipid yield of 19.7% was
achieved in ultra sonication method, whereas in normal extraction
(control) the maximum lipid yield was recorded 13.4%. The lipid
yield was increased about double the amount in ultrasonication
method when compared to control, thus this pre-treatment
technique was used for further study. An autoclave method is a
heat treatment technique incorporated for lipid extraction from
the algal cells by destructing the cell membranes to enhance the
extraction efficiency for high yield. As a result of this process, the
maximum extraction yield was achieved upto 17.2%. Hence,
the heat treatment method is also one of the very efficient
technique. Similarly, deep-freezing and microwave pre-treatment
methods caused partial hydrolysis and pre-esterification of the
algal lipids and these pre-treatment methods did not show high
activity in lipid extraction. Chloroform methanol is a constant
solvent used for the entire pre-treatments process.